Crystallization is the process in which solid matters are precipitated from steam, solution or melts in the crystal state. The traditional industrial crystallization research field, generally, can be divided into four categories, i.e., solution crystallization, melt crystallization, precipitate crystallization and sublimation crystallization.
Crystallization equipment is important unit chemical equipment. At present, cooling crystallization equipment mainly applies dividing wall cooling crystallization equipment and vacuum cooling crystallization equipment, wherein most of the dividing wall cooling crystallization equipment is provided with jacket cooling crystallization tanks, which are high in water consumption, easy in scaling on the heat exchange surface and low in cooling production efficiency; and the vacuum cooling crystallization equipment is only used in minority of enterprises, and generally, owing to sprayed vacuumizing under steam, the energy consumption of steam is higher. In order to overcome the defects and deficiencies of the dividing wall cooling crystallization equipment and the vacuum crystallization equipment, the air-cooled crystallization column has been applied in the cooling crystallization of chemical industry production, however, the problems of high volume and energy consumption of the crystallization column still exit.
In addition, the existing crystallization column has the problems of difficult dropping of crystal substances, high energy consumption and low concentration of acidic water formed, resulting in resource wastes. For example, the conventional crystallization column structure formed by multiple layers of perforated plates is complex and high in costs, crystal substances are easy to enrich and can be firmly bound to the crystallization plate without dropping, and are required to be dropped by means of the periodic vibration of additional vibration equipment on the crystallization column, resulting in high energy consumption. In addition, the blockage of crystal substances on perforated holes is also required to be prevented, and even shutdown is also required at variable intervals to maintain or assist the dropping of crystal substances, achieving low efficiency of crystallization column. In addition, when the crystal substances are difficult to drop, for high water volume for washing crystal substances and low concentration of acidic water formed, it is the problem to be solved during the design of the crystallization column.